you are exactly searching for what?? May be this is your answer... Generally this is when advertisers track your movements. The goal is to make a profile of you (interests, age, gender, wealth etc). With this information they can better target ads that might interest you. A good example is the Amazon.com homepage. It changes a lot based on what you look at on the site. Read more: http://wiki.answers.com/Q/What_is_cross_site_profiling#ixzz1IuT6XDIT